Conventionally, at startup of a fuel cell system, the air staying in an anode flow channel of the fuel cell makes a flow circulating in a circulation flow channel of an anode system through a circulation device such as a circulation pump. Hereby, mixing of supplied hydrogen with the air staying in the anode flow channel is promoted, and elimination of a hydrogen concentration gradient between an inlet side and an outlet side of the anode flow channel of the fuel cell is achieved. Further, at startup of the fuel cell system, a purge (hereinafter, referred to as a “startup purge”) for discharging the air staying in the anode flow channel is performed during circulation through the circulation device (refer to Patent Document 1 below).